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			<h2 class="mark_title">第二章作业-2021</h2>
			<div class="infoHead">
				<span>题量: 70</span>
				<span>满分: 100</span>
				<p class="rightBord">作答时间:<em>12-01 14:34</em>至<em>12-05 23:59</em></p>
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							<span class="resultNum"><i>100</i>分</span>
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					<div class="mark_item">
						                            <h2 class="type_tit">一. 单选题（共29题，40.6分）</h2>
																			
																												<div class="marBom60 questionLi" id="question401616894" data="401616894">
								<h3 class="mark_name colorDeep">1. <span class="colorShallow">(单选题)</span>下列选项中属于专门的关系运算的是</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A. &nbsp; &nbsp;并</li>
																													<li>B. &nbsp; &nbsp;笛卡儿积</li>
																																							<li>C. &nbsp; &nbsp;投影</li>
																													<li>D. &nbsp; &nbsp;差</li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> C</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> C</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616895" data="401616895">
								<h3 class="mark_name colorDeep">2. <span class="colorShallow">(单选题)</span>一个域允许的不同取值个数称为这个域的?</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     元组 </li>
																																							<li>B.     基数 </li>
																													<li>C.     分量 </li>
																													<li>D.     集合 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> B</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> B</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616896" data="401616896">
								<h3 class="mark_name colorDeep">3. <span class="colorShallow">(单选题)</span>下列哪个不属于数据库技术发展的阶段?</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A. &nbsp; &nbsp;人工管理阶段</li>
																													<li>B. &nbsp; &nbsp;文件系统阶段</li>
																													<li>C. &nbsp; &nbsp;数据库系统阶段</li>
																																							<li>D. &nbsp; &nbsp;人工智能阶段</li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> D</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> D</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616897" data="401616897">
								<h3 class="mark_name colorDeep">4. <span class="colorShallow">(单选题)</span>下列哪个不是关系模型的组成</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A. 关系数据结构</li>
																																							<li>B. 关系运算集合</li>
																													<li>C. 关系操作</li>
																													<li>D. 关系完整性的约束</li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> B</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> B</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

																				<div class="analysisDiv">
											<div class="analysis"><i>答案解析：</i>  </div>
										</div>
										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616898" data="401616898">
								<h3 class="mark_name colorDeep">5. <span class="colorShallow">(单选题)</span>关系运算中花费时间可能最长的运算是</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     投影 </li>
																													<li>B.     选择 </li>
																													<li>C.     除 </li>
																																							<li>D.     笛卡儿积 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> D</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> D</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616899" data="401616899">
								<h3 class="mark_name colorDeep">6. <span class="colorShallow">(单选题)</span>数据库的组成模式包括</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     关系数据结构 </li>
																													<li>B.     关系操作集合 </li>
																													<li>C.     关系完整性的约束 </li>
																																							<li>D.     以上都是 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> D</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> D</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616900" data="401616900">
								<h3 class="mark_name colorDeep">7. <span class="colorShallow">(单选题)</span>关系代数的5种基本基本运算是</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     并、差、选择、投影、自然连接 </li>
																													<li>B.     并、差、交、选择、投影 </li>
																													<li>C.     并、差、交、选择、笛卡尔积 </li>
																																							<li>D.     并、差、选择、投影、笛卡尔积 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> D</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> D</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616901" data="401616901">
								<h3 class="mark_name colorDeep">8. <span class="colorShallow">(单选题)</span>参加差运算的两个关系</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     属性个数可以不相同 </li>
																																							<li>B.     属性个数必须相同 </li>
																													<li>C.     一个关系包含另一个关系的属性 </li>
																													<li>D.     属性名必须相同 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> B</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> B</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616903" data="401616903">
								<h3 class="mark_name colorDeep">9. <span class="colorShallow">(单选题)</span>自然连接是构成新关系的有效方法。一般情况下,当对关系R和S使用自然连接时,要求R和S含有一个或多个共有的()</h3>
																	<ul class="mark_letter colorDeep">
																																							<li>A.     属性 </li>
																													<li>B.     记录 </li>
																													<li>C.     行 </li>
																													<li>D.     元组 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> A</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> A</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616904" data="401616904">
								<h3 class="mark_name colorDeep">10. <span class="colorShallow">(单选题)</span>下列哪个名词的定义为“一组具有相同数据类型的值的集合”?( )</h3>
																	<ul class="mark_letter colorDeep">
																																							<li>A. &nbsp; &nbsp;域</li>
																													<li>B. &nbsp; &nbsp;基数</li>
																													<li>C. &nbsp; &nbsp;分量</li>
																													<li>D. &nbsp; &nbsp;元组</li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> A</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> A</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616905" data="401616905">
								<h3 class="mark_name colorDeep">11. <span class="colorShallow">(单选题)</span>下列不是基本关系具有的性质的是</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     列和行的顺序无所谓 </li>
																																							<li>B.     元组间的候选码可以相同 </li>
																													<li>C.     分量必须取原子量 </li>
																													<li>D.     不同的列可以出自同一个域 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> B</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> B</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616906" data="401616906">
								<h3 class="mark_name colorDeep">12. <span class="colorShallow">(单选题)</span>五种基本关系代数运算是</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     ∪,∩,×,π和σ </li>
																													<li>B.     ∪,-,∞,π和σ </li>
																																							<li>C.     ∪, -,×,π和σ </li>
																													<li>D.     ∪,∩,∞,π和σ </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> C</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> C</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616909" data="401616909">
								<h3 class="mark_name colorDeep">13. <span class="colorShallow">(单选题)</span>下列不属于传统集合运算的是</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     并 </li>
																													<li>B.     交 </li>
																																							<li>C.     连接 </li>
																													<li>D.     笛卡尔积 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> C</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> C</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616910" data="401616910">
								<h3 class="mark_name colorDeep">14. <span class="colorShallow">(单选题)</span>若关系中的某一属性组的值能唯一的标识一个元组,而其子集不能,则称该属性组为（ &nbsp;）。</h3>
																	<ul class="mark_letter colorDeep">
																																							<li>A. &nbsp; &nbsp;候选码</li>
																													<li>B. &nbsp; &nbsp;主码</li>
																													<li>C. &nbsp; &nbsp;外码</li>
																													<li>D. &nbsp; &nbsp;全码</li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> A</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> A</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

																				<div class="analysisDiv">
											<div class="analysis"><i>答案解析：</i>  </div>
										</div>
										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616911" data="401616911">
								<h3 class="mark_name colorDeep">15. <span class="colorShallow">(单选题)</span>在一个关系中不能相同的是</h3>
																	<ul class="mark_letter colorDeep">
																																							<li>A. &nbsp; &nbsp;记录</li>
																													<li>B. &nbsp; &nbsp;域</li>
																													<li>C. &nbsp; &nbsp;分量</li>
																													<li>D. &nbsp;以上都对</li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> A</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> A</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616912" data="401616912">
								<h3 class="mark_name colorDeep">16. <span class="colorShallow">(单选题)</span>专门的关系运算包括选择,投影,连接,除运算等。其中从行的角度进行的运算是</h3>
																	<ul class="mark_letter colorDeep">
																																							<li>A.     选择 </li>
																													<li>B.     投影 </li>
																													<li>C.     连接 </li>
																													<li>D.     差 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> A</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> A</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616913" data="401616913">
								<h3 class="mark_name colorDeep">17. <span class="colorShallow">(单选题)</span>关系模型中,一个候选码是</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     可由多个任意属性组成 </li>
																													<li>B.     至多由一个属性组成 </li>
																																							<li>C.     可由一个或多个其值能唯一标识该关系模式中任何元组的属性组成 </li>
																													<li>D.     以上都不是 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> C</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> C</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616914" data="401616914">
								<h3 class="mark_name colorDeep">18. <span class="colorShallow">(单选题)</span>在数据库的三级结构中,描述数据库中全体数据的全局逻辑结构和结构特征的是</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     外模式 </li>
																																							<li>B.     模式 </li>
																													<li>C.     内模式 </li>
																													<li>D.     存储模式 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> B</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> B</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616915" data="401616915">
								<h3 class="mark_name colorDeep">19. <span class="colorShallow">(单选题)</span>模式关系操作的对象和结果都是</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     数据 </li>
																													<li>B.     元素 </li>
																																							<li>C.     集合 </li>
																													<li>D.     数组 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> C</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> C</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616916" data="401616916">
								<h3 class="mark_name colorDeep">20. <span class="colorShallow">(单选题)</span>关系模型中常用的关系操作包括查询操作和( )操作两大部分</h3>
																	<ul class="mark_letter colorDeep">
																																							<li>A.     更新 </li>
																													<li>B.     插入 </li>
																													<li>C.     删除 </li>
																													<li>D.     修改 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> A</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> A</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616917" data="401616917">
								<h3 class="mark_name colorDeep">21. <span class="colorShallow">(单选题)</span>关系数据库的型也称为关系数据库模式,是对()的描述</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     数据 </li>
																																							<li>B.     关系数据库 </li>
																													<li>C.     数据库管理系统 </li>
																													<li>D.     数据库 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> B</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> B</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616918" data="401616918">
								<h3 class="mark_name colorDeep">22. <span class="colorShallow">(单选题)</span>在关系R(R#,RN,S#)和S(S#,SN,SD)中,R的主键是R#,S的主键是S#,则S#在R中称为</h3>
																	<ul class="mark_letter colorDeep">
																																							<li>A.     外键 </li>
																													<li>B.     候选键 </li>
																													<li>C.     主键 </li>
																													<li>D.     以上都不是  </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> A</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> A</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616919" data="401616919">
								<h3 class="mark_name colorDeep">23. <span class="colorShallow">(单选题)</span>传统的集合运算是二目运算,包括并、差 、交、 ()四中运算。</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     选择 </li>
																													<li>B.     投影 </li>
																													<li>C.     除运算 </li>
																																							<li>D.     笛卡尔积 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> D</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> D</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616920" data="401616920">
								<h3 class="mark_name colorDeep">24. <span class="colorShallow">(单选题)</span>根据参照完整性规则,对于基本关系R中的每个元组在外码上的值必须是()</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A. &nbsp; &nbsp;空值</li>
																													<li>B. &nbsp; &nbsp;基本关系S中某个元组的主码值</li>
																													<li>C. &nbsp; A和B</li>
																																							<li>D. &nbsp; &nbsp;A或B</li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> D</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> D</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

																				<div class="analysisDiv">
											<div class="analysis"><i>答案解析：</i>  </div>
										</div>
										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616921" data="401616921">
								<h3 class="mark_name colorDeep">25. <span class="colorShallow">(单选题)</span>若一个关系有多个候选码,则选定其中一个为()</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     主属性 </li>
																																							<li>B.     主码 </li>
																													<li>C.     全码 </li>
																													<li>D.     主候选码 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> B</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> B</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616922" data="401616922">
								<h3 class="mark_name colorDeep">26. <span class="colorShallow">(单选题)</span>关系有三种类型:基本表、( )、视图表</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     有序表 </li>
																													<li>B.     无序表 </li>
																																							<li>C.     查询表 </li>
																													<li>D.     模型表 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> C</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> C</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616923" data="401616923">
								<h3 class="mark_name colorDeep">27. <span class="colorShallow">(单选题)</span>不是关系模型中的完整性约束的是( )</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     实体完整性 </li>
																																							<li>B.     属性完整性 </li>
																													<li>C.     参照完整性 </li>
																													<li>D.     用户定义的完整性 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> B</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> B</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616924" data="401616924">
								<h3 class="mark_name colorDeep">28. <span class="colorShallow">(单选题)</span>假设存在一张职工表,包含“性别”属性,要求这个属性的值只能取“男”或“女”,这属于()</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     实体完整性 </li>
																													<li>B.     属性完整性 </li>
																													<li>C.     参照完整性 </li>
																																							<li>D.     用户定义的完整性 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> D</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> D</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616925" data="401616925">
								<h3 class="mark_name colorDeep">29. <span class="colorShallow">(单选题)</span>有两个关系R(A,B,C)和S(B,C,D),将R和S进行自然连接,得到的结果包含( )列</h3>
																	<ul class="mark_letter colorDeep">
																													<li>A.     3 </li>
																																							<li>B.     4 </li>
																													<li>C.     5 </li>
																													<li>D.     6 </li>
																		</ul>
									
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> B</span>
																						<span class="colorGreen marginRight40 fl"><i class="fontWeight">正确答案:</i> B</span>
																					</div>
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																										<span class="marking_dui"></span>
																									</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>

										
									</div>

															</div>
											</div>
									
																						
					
																					
					<div class="mark_item">
						                            <h2 class="type_tit">二. 填空题（共13题，18.2分）</h2>
																			
																												<div class="marBom60 questionLi" id="question401616926" data="401616926">
								<h3 class="mark_name colorDeep">30. <span class="colorShallow">(填空题)</span>关系模型中常用的关系操作包括查询操作、插入、删除、<span style="text-decoration: underline;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;</span>操作。</h3>
																	<div class="mark_answer" style="width:760px;">
										<div>
											<dl class="mark_fill colorDeep" id="qb401616926">
												<dt class="positionStyle">
													<i class="fontWeight">我的答案：</i>
																										<div class="mark_score">
														<div class=" fl catalog_tishi80">
															<div class="mark_judge_name"></div>
														</div>
														<div class="totalScore fr"><i>1.4</i>分</div>
													</div>
																									</dt>
																																																																			
														<dd>
															<span class="answer_span" style="display:inline-block;width:94%;">(1) 修改</span>
																																															                                                                <span class="marking_dui"></span>
																																																												</dd>
																																				</dl>
											
																						<dl class="mark_fill colorGreen">
												<dt><i class="fontWeight">正确答案：</i></dt>
														    																																																				<dd>(1) 修改;update</dd>
		    																																	</dl>
																					</div>

																				<div class="analysisDiv">
											<div class="analysis"><i>答案解析：</i>  </div>
										</div>
										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616927" data="401616927">
								<h3 class="mark_name colorDeep">31. <span class="colorShallow">(填空题)</span>关系可以有三种类型:基本关系、查询表和<span style="text-decoration: underline;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </span><span style="text-decoration: none;">。</span></h3>
																	<div class="mark_answer" style="width:760px;">
										<div>
											<dl class="mark_fill colorDeep" id="qb401616927">
												<dt class="positionStyle">
													<i class="fontWeight">我的答案：</i>
																										<div class="mark_score">
														<div class=" fl catalog_tishi80">
															<div class="mark_judge_name"></div>
														</div>
														<div class="totalScore fr"><i>1.4</i>分</div>
													</div>
																									</dt>
																																																																			
														<dd>
															<span class="answer_span" style="display:inline-block;width:94%;">(1) 视图</span>
																																															                                                                <span class="marking_dui"></span>
																																																												</dd>
																																				</dl>
											
																						<dl class="mark_fill colorGreen">
												<dt><i class="fontWeight">正确答案：</i></dt>
														    																																																				<dd>(1) &nbsp; &nbsp;视图;view；视图表</dd>
		    																																	</dl>
																					</div>

																				<div class="analysisDiv">
											<div class="analysis"><i>答案解析：</i>  </div>
										</div>
										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616928" data="401616928">
								<h3 class="mark_name colorDeep">32. <span class="colorShallow">(填空题)</span>可以唯一标识一个元组的属性组叫候选码 ,人为选择的候选码叫<span style="text-decoration: underline;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </span>。</h3>
																	<div class="mark_answer" style="width:760px;">
										<div>
											<dl class="mark_fill colorDeep" id="qb401616928">
												<dt class="positionStyle">
													<i class="fontWeight">我的答案：</i>
																										<div class="mark_score">
														<div class=" fl catalog_tishi80">
															<div class="mark_judge_name"></div>
														</div>
														<div class="totalScore fr"><i>1.4</i>分</div>
													</div>
																									</dt>
																																																																			
														<dd>
															<span class="answer_span" style="display:inline-block;width:94%;">(1) 主码</span>
																																															                                                                <span class="marking_dui"></span>
																																																												</dd>
																																				</dl>
											
																						<dl class="mark_fill colorGreen">
												<dt><i class="fontWeight">正确答案：</i></dt>
														    																																																				<dd>(1) &nbsp; &nbsp;主码;主键</dd>
		    																																	</dl>
																					</div>

																				<div class="analysisDiv">
											<div class="analysis"><i>答案解析：</i>  </div>
										</div>
										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616929" data="401616929">
								<h3 class="mark_name colorDeep">33. <span class="colorShallow">(填空题)</span>传统的集合运算包括并、差、交、<span style="text-decoration: underline;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </span>。</h3>
																	<div class="mark_answer" style="width:760px;">
										<div>
											<dl class="mark_fill colorDeep" id="qb401616929">
												<dt class="positionStyle">
													<i class="fontWeight">我的答案：</i>
																										<div class="mark_score">
														<div class=" fl catalog_tishi80">
															<div class="mark_judge_name"></div>
														</div>
														<div class="totalScore fr"><i>1.4</i>分</div>
													</div>
																									</dt>
																																																																			
														<dd>
															<span class="answer_span" style="display:inline-block;width:94%;">(1) 笛卡尔积</span>
																																															                                                                <span class="marking_dui"></span>
																																																												</dd>
																																				</dl>
											
																						<dl class="mark_fill colorGreen">
												<dt><i class="fontWeight">正确答案：</i></dt>
														    																																																				<dd>(1) &nbsp; &nbsp;笛卡尔积</dd>
		    																																	</dl>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616930" data="401616930">
								<h3 class="mark_name colorDeep">34. <span class="colorShallow">(填空题)</span>关系的完整性约束条件包括三大类:分别是实体完整性、<span style="text-decoration: underline;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;</span>和用户定义的完整性。</h3>
																	<div class="mark_answer" style="width:760px;">
										<div>
											<dl class="mark_fill colorDeep" id="qb401616930">
												<dt class="positionStyle">
													<i class="fontWeight">我的答案：</i>
																										<div class="mark_score">
														<div class=" fl catalog_tishi80">
															<div class="mark_judge_name"></div>
														</div>
														<div class="totalScore fr"><i>1.4</i>分</div>
													</div>
																									</dt>
																																																																			
														<dd>
															<span class="answer_span" style="display:inline-block;width:94%;">(1) 参照完整性</span>
																																															                                                                <span class="marking_dui"></span>
																																																												</dd>
																																				</dl>
											
																						<dl class="mark_fill colorGreen">
												<dt><i class="fontWeight">正确答案：</i></dt>
														    																																																				<dd>(1) &nbsp; &nbsp;参照完整性</dd>
		    																																	</dl>
																					</div>

																				<div class="analysisDiv">
											<div class="analysis"><i>答案解析：</i>  </div>
										</div>
										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616932" data="401616932">
								<h3 class="mark_name colorDeep">35. <span class="colorShallow">(填空题)</span>关系模型中有三类完整性约束:实体完整性、用户定义的完整性和参照完整性。其中_________和参照完整性被称作是关系的两个不变性。</h3>
																	<div class="mark_answer" style="width:760px;">
										<div>
											<dl class="mark_fill colorDeep" id="qb401616932">
												<dt class="positionStyle">
													<i class="fontWeight">我的答案：</i>
																										<div class="mark_score">
														<div class=" fl catalog_tishi80">
															<div class="mark_judge_name"></div>
														</div>
														<div class="totalScore fr"><i>1.4</i>分</div>
													</div>
																									</dt>
																																																																			
														<dd>
															<span class="answer_span" style="display:inline-block;width:94%;">(1) 实体完整性</span>
																																															                                                                <span class="marking_dui"></span>
																																																												</dd>
																																				</dl>
											
																						<dl class="mark_fill colorGreen">
												<dt><i class="fontWeight">正确答案：</i></dt>
														    																																																				<dd>(1) &nbsp; &nbsp;实体完整性</dd>
		    																																	</dl>
																					</div>

																				<div class="analysisDiv">
											<div class="analysis"><i>答案解析：</i>  </div>
										</div>
										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616934" data="401616934">
								<h3 class="mark_name colorDeep">36. <span class="colorShallow">(填空题)</span>关系模式是静态的,___________</h3>
																	<div class="mark_answer" style="width:760px;">
										<div>
											<dl class="mark_fill colorDeep" id="qb401616934">
												<dt class="positionStyle">
													<i class="fontWeight">我的答案：</i>
																										<div class="mark_score">
														<div class=" fl catalog_tishi80">
															<div class="mark_judge_name"></div>
														</div>
														<div class="totalScore fr"><i>1.4</i>分</div>
													</div>
																									</dt>
																																																																			
														<dd>
															<span class="answer_span" style="display:inline-block;width:94%;">(1) 稳定的</span>
																																															                                                                <span class="marking_dui"></span>
																																																												</dd>
																																				</dl>
											
																						<dl class="mark_fill colorGreen">
												<dt><i class="fontWeight">正确答案：</i></dt>
														    																																																				<dd>(1)     稳定的 </dd>
		    																																	</dl>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616935" data="401616935">
								<h3 class="mark_name colorDeep">37. <span class="colorShallow">(填空题)</span>关系的描述称为关系模式。它可以形式化的表示为<span style="text-decoration: underline;">&nbsp; &nbsp; &nbsp; &nbsp;</span>(&nbsp;<span style="text-decoration: underline;">&nbsp; &nbsp; &nbsp; &nbsp;</span>、D、DOM和F)</h3>
																	<div class="mark_answer" style="width:760px;">
										<div>
											<dl class="mark_fill colorDeep" id="qb401616935">
												<dt class="positionStyle">
													<i class="fontWeight">我的答案：</i>
																										<div class="mark_score">
														<div class=" fl catalog_tishi80">
															<div class="mark_judge_name"></div>
														</div>
														<div class="totalScore fr"><i>1.4</i>分</div>
													</div>
																									</dt>
																																																																			
														<dd>
															<span class="answer_span" style="display:inline-block;width:94%;">(1) R</span>
																																															                                                                <span class="marking_dui"></span>
																																																												</dd>
																																																							
														<dd>
															<span class="answer_span" style="display:inline-block;width:94%;">(2) U</span>
																																															                                                                <span class="marking_dui"></span>
																																																												</dd>
																																				</dl>
											
																						<dl class="mark_fill colorGreen">
												<dt><i class="fontWeight">正确答案：</i></dt>
														    																																																				<dd>(1) &nbsp; &nbsp;R</dd>
		    																																																				<dd>(2) U</dd>
		    																																	</dl>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616936" data="401616936">
								<h3 class="mark_name colorDeep">38. <span class="colorShallow">(填空题)</span>_______连接是一种特殊的等值连接。</h3>
																	<div class="mark_answer" style="width:760px;">
										<div>
											<dl class="mark_fill colorDeep" id="qb401616936">
												<dt class="positionStyle">
													<i class="fontWeight">我的答案：</i>
																										<div class="mark_score">
														<div class=" fl catalog_tishi80">
															<div class="mark_judge_name"></div>
														</div>
														<div class="totalScore fr"><i>1.4</i>分</div>
													</div>
																									</dt>
																																																																			
														<dd>
															<span class="answer_span" style="display:inline-block;width:94%;">(1) 自然</span>
																																															                                                                <span class="marking_dui"></span>
																																																												</dd>
																																				</dl>
											
																						<dl class="mark_fill colorGreen">
												<dt><i class="fontWeight">正确答案：</i></dt>
														    																																																				<dd>(1) &nbsp; 自然；自然连接</dd>
		    																																	</dl>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616937" data="401616937">
								<h3 class="mark_name colorDeep">39. <span class="colorShallow">(填空题)</span>______是一组具有相同数据类型的值的集合。</h3>
																	<div class="mark_answer" style="width:760px;">
										<div>
											<dl class="mark_fill colorDeep" id="qb401616937">
												<dt class="positionStyle">
													<i class="fontWeight">我的答案：</i>
																										<div class="mark_score">
														<div class=" fl catalog_tishi80">
															<div class="mark_judge_name"></div>
														</div>
														<div class="totalScore fr"><i>1.4</i>分</div>
													</div>
																									</dt>
																																																																			
														<dd>
															<span class="answer_span" style="display:inline-block;width:94%;">(1) 域</span>
																																															                                                                <span class="marking_dui"></span>
																																																												</dd>
																																				</dl>
											
																						<dl class="mark_fill colorGreen">
												<dt><i class="fontWeight">正确答案：</i></dt>
														    																																																				<dd>(1) &nbsp; &nbsp;域</dd>
		    																																	</dl>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616938" data="401616938">
								<h3 class="mark_name colorDeep">40. <span class="colorShallow">(填空题)</span>关系模式的所有属性是这个关系模式的候选码称为______。</h3>
																	<div class="mark_answer" style="width:760px;">
										<div>
											<dl class="mark_fill colorDeep" id="qb401616938">
												<dt class="positionStyle">
													<i class="fontWeight">我的答案：</i>
																										<div class="mark_score">
														<div class=" fl catalog_tishi80">
															<div class="mark_judge_name"></div>
														</div>
														<div class="totalScore fr"><i>1.4</i>分</div>
													</div>
																									</dt>
																																																																			
														<dd>
															<span class="answer_span" style="display:inline-block;width:94%;">(1) 全码</span>
																																															                                                                <span class="marking_dui"></span>
																																																												</dd>
																																				</dl>
											
																						<dl class="mark_fill colorGreen">
												<dt><i class="fontWeight">正确答案：</i></dt>
														    																																																				<dd>(1) &nbsp; &nbsp;全码</dd>
		    																																	</dl>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616939" data="401616939">
								<h3 class="mark_name colorDeep">41. <span class="colorShallow">(填空题)</span>关系的每一个分量必须是一个<span style="text-decoration: underline;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;</span> 的数据项。</h3>
																	<div class="mark_answer" style="width:760px;">
										<div>
											<dl class="mark_fill colorDeep" id="qb401616939">
												<dt class="positionStyle">
													<i class="fontWeight">我的答案：</i>
																										<div class="mark_score">
														<div class=" fl catalog_tishi80">
															<div class="mark_judge_name"></div>
														</div>
														<div class="totalScore fr"><i>1.4</i>分</div>
													</div>
																									</dt>
																																																																			
														<dd>
															<span class="answer_span" style="display:inline-block;width:94%;">(1) 不可分</span>
																																															                                                                <span class="marking_dui"></span>
																																																												</dd>
																																				</dl>
											
																						<dl class="mark_fill colorGreen">
												<dt><i class="fontWeight">正确答案：</i></dt>
														    																																																				<dd>(1) &nbsp; &nbsp;不可分；不可再分</dd>
		    																																	</dl>
																					</div>

										
									</div>

															</div>
													
																												<div class="marBom60 questionLi" id="question401616940" data="401616940">
								<h3 class="mark_name colorDeep">42. <span class="colorShallow">(填空题)</span>关系代数的运算按运算符的不同可以分为传统的集合运算和______</h3>
																	<div class="mark_answer" style="width:760px;">
										<div>
											<dl class="mark_fill colorDeep" id="qb401616940">
												<dt class="positionStyle">
													<i class="fontWeight">我的答案：</i>
																										<div class="mark_score">
														<div class=" fl catalog_tishi80">
															<div class="mark_judge_name"></div>
														</div>
														<div class="totalScore fr"><i>1.4</i>分</div>
													</div>
																									</dt>
																																																																			
														<dd>
															<span class="answer_span" style="display:inline-block;width:94%;">(1) 专门的关系运算</span>
																																															                                                                <span class="marking_dui"></span>
																																																												</dd>
																																				</dl>
											
																						<dl class="mark_fill colorGreen">
												<dt><i class="fontWeight">正确答案：</i></dt>
														    																																																				<dd>(1) &nbsp; &nbsp;专门的关系运算</dd>
		    																																	</dl>
																					</div>

																				<div class="analysisDiv">
											<div class="analysis"><i>答案解析：</i>  </div>
										</div>
										
									</div>

															</div>
											</div>
									
																						
					
																					
					<div class="mark_item">
						                            <h2 class="type_tit">三. 判断题（共28题，41.2分）</h2>
																			
																												<div class="marBom60 questionLi" id="question401616941" data="401616941">
								<h3 class="mark_name colorDeep">43. <span class="colorShallow">(判断题)</span>关系可以有三种类型:基本关系、查询表和视图表。</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 对</span>
																						<span class="colorGreen marginRight40 fl">
																											        										<i class="fontWeight">正确答案:</i> 对
		            										            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616942" data="401616942">
								<h3 class="mark_name colorDeep">44. <span class="colorShallow">(判断题)</span>实体完整性规则是针对基本关系而言的。</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 对</span>
																						<span class="colorGreen marginRight40 fl">
																											        										<i class="fontWeight">正确答案:</i> 对
		            										            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616943" data="401616943">
								<h3 class="mark_name colorDeep">45. <span class="colorShallow">(判断题)</span>关系是关系模式在任何时刻的状态或内容。</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 错</span>
																						<span class="colorGreen marginRight40 fl">
																											            										        										<i class="fontWeight">正确答案:</i> 错
		            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616944" data="401616944">
								<h3 class="mark_name colorDeep">46. <span class="colorShallow">(判断题)</span>关系是迪卡尔积的一个子集。</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 对</span>
																						<span class="colorGreen marginRight40 fl">
																											        										<i class="fontWeight">正确答案:</i> 对
		            										            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616945" data="401616945">
								<h3 class="mark_name colorDeep">47. <span class="colorShallow">(判断题)</span>选择又称为限制</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 对</span>
																						<span class="colorGreen marginRight40 fl">
																											        										<i class="fontWeight">正确答案:</i> 对
		            										            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616946" data="401616946">
								<h3 class="mark_name colorDeep">48. <span class="colorShallow">(判断题)</span>参照完整性是指基本关系R 的主属性不能取空值。</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 错</span>
																						<span class="colorGreen marginRight40 fl">
																											            										        										<i class="fontWeight">正确答案:</i> 错
		            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616947" data="401616947">
								<h3 class="mark_name colorDeep">49. <span class="colorShallow">(判断题)</span>关系模型中,一个候选码可由一个或多个其值能唯一标识该关系模式中任何元组的属性组成。</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 对</span>
																						<span class="colorGreen marginRight40 fl">
																											        										<i class="fontWeight">正确答案:</i> 对
		            										            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616948" data="401616948">
								<h3 class="mark_name colorDeep">50. <span class="colorShallow">(判断题)</span>关系的描述称为关系模式。</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 对</span>
																						<span class="colorGreen marginRight40 fl">
																											        										<i class="fontWeight">正确答案:</i> 对
		            										            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616949" data="401616949">
								<h3 class="mark_name colorDeep">51. <span class="colorShallow">(判断题)</span>.若一组关系中的某一属性组的值能唯一地标识一个元组,而其子集不能,则称该属性组为全码。</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 错</span>
																						<span class="colorGreen marginRight40 fl">
																											            										        										<i class="fontWeight">正确答案:</i> 错
		            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616950" data="401616950">
								<h3 class="mark_name colorDeep">52. <span class="colorShallow">(判断题)</span>选择运算是从行的角度进行的运算。</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 对</span>
																						<span class="colorGreen marginRight40 fl">
																											        										<i class="fontWeight">正确答案:</i> 对
		            										            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616951" data="401616951">
								<h3 class="mark_name colorDeep">53. <span class="colorShallow">(判断题)</span>关系操作的特点是集合操作方式。</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 对</span>
																						<span class="colorGreen marginRight40 fl">
																											        										<i class="fontWeight">正确答案:</i> 对
		            										            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616952" data="401616952">
								<h3 class="mark_name colorDeep">54. <span class="colorShallow">(判断题)</span>外模式/模式映像保证了数据的物理独立性。</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 错</span>
																						<span class="colorGreen marginRight40 fl">
																											            										        										<i class="fontWeight">正确答案:</i> 错
		            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616954" data="401616954">
								<h3 class="mark_name colorDeep">55. <span class="colorShallow">(判断题)</span>主码中的属性称为主属性</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 错</span>
																						<span class="colorGreen marginRight40 fl">
																											            										        										<i class="fontWeight">正确答案:</i> 错
		            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616955" data="401616955">
								<h3 class="mark_name colorDeep">56. <span class="colorShallow">(判断题)</span>关系操作的对象和结果都是集合</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 对</span>
																						<span class="colorGreen marginRight40 fl">
																											        										<i class="fontWeight">正确答案:</i> 对
		            										            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616956" data="401616956">
								<h3 class="mark_name colorDeep">57. <span class="colorShallow">(判断题)</span>自然连接是一种特殊的等值连接。</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 对</span>
																						<span class="colorGreen marginRight40 fl">
																											        										<i class="fontWeight">正确答案:</i> 对
		            										            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616957" data="401616957">
								<h3 class="mark_name colorDeep">58. <span class="colorShallow">(判断题)</span>在一个关系模式中,有可能没有非主属性。</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 对</span>
																						<span class="colorGreen marginRight40 fl">
																											        										<i class="fontWeight">正确答案:</i> 对
		            										            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
																				<div class="analysisDiv">
											<div class="analysis"><i>答案解析：</i>      </div>
										</div>
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616958" data="401616958">
								<h3 class="mark_name colorDeep">59. <span class="colorShallow">(判断题)</span>关系代数运算的基础是集合运算</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 对</span>
																						<span class="colorGreen marginRight40 fl">
																											        										<i class="fontWeight">正确答案:</i> 对
		            										            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616959" data="401616959">
								<h3 class="mark_name colorDeep">60. <span class="colorShallow">(判断题)</span>关系模式是静态的、稳定的,而关系是动态的、随时间不断变化的。</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 对</span>
																						<span class="colorGreen marginRight40 fl">
																											        										<i class="fontWeight">正确答案:</i> 对
		            										            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616960" data="401616960">
								<h3 class="mark_name colorDeep">61. <span class="colorShallow">(判断题)</span>传统的集合运算是二目运算,包括并、差、交、迪卡儿积4种运算。</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 对</span>
																						<span class="colorGreen marginRight40 fl">
																											        										<i class="fontWeight">正确答案:</i> 对
		            										            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616961" data="401616961">
								<h3 class="mark_name colorDeep">62. <span class="colorShallow">(判断题)</span>关系模式是指关系的描述</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 对</span>
																						<span class="colorGreen marginRight40 fl">
																											        										<i class="fontWeight">正确答案:</i> 对
		            										            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616962" data="401616962">
								<h3 class="mark_name colorDeep">63. <span class="colorShallow">(判断题)</span>一个关系中可以有多个候选码和主码</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 错</span>
																						<span class="colorGreen marginRight40 fl">
																											            										        										<i class="fontWeight">正确答案:</i> 错
		            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616963" data="401616963">
								<h3 class="mark_name colorDeep">64. <span class="colorShallow">(判断题)</span>在参照完整性中,外码不可以取空值</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 错</span>
																						<span class="colorGreen marginRight40 fl">
																											            										        										<i class="fontWeight">正确答案:</i> 错
		            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616964" data="401616964">
								<h3 class="mark_name colorDeep">65. <span class="colorShallow">(判断题)</span>外码一定要与相应的主码同名</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 错</span>
																						<span class="colorGreen marginRight40 fl">
																											            										        										<i class="fontWeight">正确答案:</i> 错
		            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616965" data="401616965">
								<h3 class="mark_name colorDeep">66. <span class="colorShallow">(判断题)</span>某一属性组能唯一的标识一个实体,则称该属性组为候选码</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 对</span>
																						<span class="colorGreen marginRight40 fl">
																											        										<i class="fontWeight">正确答案:</i> 对
		            										            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616966" data="401616966">
								<h3 class="mark_name colorDeep">67. <span class="colorShallow">(判断题)</span>视图表是实表</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 错</span>
																						<span class="colorGreen marginRight40 fl">
																											            										        										<i class="fontWeight">正确答案:</i> 错
		            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616967" data="401616967">
								<h3 class="mark_name colorDeep">68. <span class="colorShallow">(判断题)</span>若属性A是基本关系R的主属性,A可以取空值</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 错</span>
																						<span class="colorGreen marginRight40 fl">
																											            										        										<i class="fontWeight">正确答案:</i> 错
		            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616968" data="401616968">
								<h3 class="mark_name colorDeep">69. <span class="colorShallow">(判断题)</span>任何关系数据库系统都应该支持实体完整性和参照完整行</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 对</span>
																						<span class="colorGreen marginRight40 fl">
																											        										<i class="fontWeight">正确答案:</i> 对
		            										            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>1.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
													
																												<div class="marBom60 questionLi" id="question401616969" data="401616969">
								<h3 class="mark_name colorDeep">70. <span class="colorShallow">(判断题)</span>关系模式形式表示为R(U,D,DOM,F),其中D为属性向域映射的集合。</h3>
																	<ul class="mark_letter colorDeep">
										<li>A. 对</li>
										<li>B. 错</li>
									</ul>
									<div class="mark_answer">
										<div class="mark_key clearfix">
											<span class="colorDeep marginRight40 fl"><i class="fontWeight">我的答案:</i> 错</span>
																						<span class="colorGreen marginRight40 fl">
																											            										        										<i class="fontWeight">正确答案:</i> 错
		            																															</span>
																					</div>
										
										<div class="mark_score">
											<div class=" fl catalog_tishi80">
																								<div class="mark_judge_name">
																    									<span class="marking_dui"></span>
			    																					</div>
																							</div>
																						<div class="totalScore fr"><i>3.4</i>分</div>
																					</div>
										
										
									</div>
								
															</div>
											</div>
							</div>
			</div>
	
		<div class="fanyaMarking_right" id="rightHeight" style="max-height: 576px; top: 70px;">
		<div class="topicNumber" id="topicNumberScroll" style="max-height: 496px; overflow: hidden; outline: none;" tabindex="1">
												
																										
						
																				
                        <div class="topicNumber_checkbox colorDeep fs14">
							                                <span class="numRight fr"><i>40.6</i>分</span>
														一. 单选题（40.6分）                        </div>
                        <ul class="topicNumber_list clearfix">
							                                <li id="answerSheet401616894" data="401616894" class="active">1</li>
							                                <li id="answerSheet401616895" data="401616895" class="active">2</li>
							                                <li id="answerSheet401616896" data="401616896" class="active">3</li>
							                                <li id="answerSheet401616897" data="401616897" class="active">4</li>
							                                <li id="answerSheet401616898" data="401616898" class="active">5</li>
							                                <li id="answerSheet401616899" data="401616899" class="active">6</li>
							                                <li id="answerSheet401616900" data="401616900" class="active">7</li>
							                                <li id="answerSheet401616901" data="401616901" class="active">8</li>
							                                <li id="answerSheet401616903" data="401616903" class="active">9</li>
							                                <li id="answerSheet401616904" data="401616904" class="active">10</li>
							                                <li id="answerSheet401616905" data="401616905" class="active">11</li>
							                                <li id="answerSheet401616906" data="401616906" class="active">12</li>
							                                <li id="answerSheet401616909" data="401616909" class="active">13</li>
							                                <li id="answerSheet401616910" data="401616910" class="active">14</li>
							                                <li id="answerSheet401616911" data="401616911" class="active">15</li>
							                                <li id="answerSheet401616912" data="401616912" class="active">16</li>
							                                <li id="answerSheet401616913" data="401616913" class="active">17</li>
							                                <li id="answerSheet401616914" data="401616914" class="active">18</li>
							                                <li id="answerSheet401616915" data="401616915" class="active">19</li>
							                                <li id="answerSheet401616916" data="401616916" class="active">20</li>
							                                <li id="answerSheet401616917" data="401616917" class="active">21</li>
							                                <li id="answerSheet401616918" data="401616918" class="active">22</li>
							                                <li id="answerSheet401616919" data="401616919" class="active">23</li>
							                                <li id="answerSheet401616920" data="401616920" class="active">24</li>
							                                <li id="answerSheet401616921" data="401616921" class="active">25</li>
							                                <li id="answerSheet401616922" data="401616922" class="active">26</li>
							                                <li id="answerSheet401616923" data="401616923" class="active">27</li>
							                                <li id="answerSheet401616924" data="401616924" class="active">28</li>
							                                <li id="answerSheet401616925" data="401616925" class="active">29</li>
							                        </ul>
					
																										
						
																				
                        <div class="topicNumber_checkbox colorDeep fs14">
							                                <span class="numRight fr"><i>18.2</i>分</span>
														二. 填空题（18.2分）                        </div>
                        <ul class="topicNumber_list clearfix">
							                                <li id="answerSheet401616926" data="401616926" class="active">30</li>
							                                <li id="answerSheet401616927" data="401616927" class="active">31</li>
							                                <li id="answerSheet401616928" data="401616928" class="active">32</li>
							                                <li id="answerSheet401616929" data="401616929" class="active">33</li>
							                                <li id="answerSheet401616930" data="401616930" class="active">34</li>
							                                <li id="answerSheet401616932" data="401616932" class="active">35</li>
							                                <li id="answerSheet401616934" data="401616934" class="active">36</li>
							                                <li id="answerSheet401616935" data="401616935" class="active">37</li>
							                                <li id="answerSheet401616936" data="401616936" class="active">38</li>
							                                <li id="answerSheet401616937" data="401616937" class="active">39</li>
							                                <li id="answerSheet401616938" data="401616938" class="active">40</li>
							                                <li id="answerSheet401616939" data="401616939" class="active">41</li>
							                                <li id="answerSheet401616940" data="401616940" class="active">42</li>
							                        </ul>
					
																										
						
																				
                        <div class="topicNumber_checkbox colorDeep fs14">
							                                <span class="numRight fr"><i>41.2</i>分</span>
														三. 判断题（41.2分）                        </div>
                        <ul class="topicNumber_list clearfix">
							                                <li id="answerSheet401616941" data="401616941" class="active">43</li>
							                                <li id="answerSheet401616942" data="401616942" class="active">44</li>
							                                <li id="answerSheet401616943" data="401616943" class="active">45</li>
							                                <li id="answerSheet401616944" data="401616944" class="active">46</li>
							                                <li id="answerSheet401616945" data="401616945" class="active">47</li>
							                                <li id="answerSheet401616946" data="401616946" class="active">48</li>
							                                <li id="answerSheet401616947" data="401616947" class="active">49</li>
							                                <li id="answerSheet401616948" data="401616948" class="active">50</li>
							                                <li id="answerSheet401616949" data="401616949" class="active">51</li>
							                                <li id="answerSheet401616950" data="401616950" class="active">52</li>
							                                <li id="answerSheet401616951" data="401616951" class="active">53</li>
							                                <li id="answerSheet401616952" data="401616952" class="active">54</li>
							                                <li id="answerSheet401616954" data="401616954" class="active">55</li>
							                                <li id="answerSheet401616955" data="401616955" class="active">56</li>
							                                <li id="answerSheet401616956" data="401616956" class="active">57</li>
							                                <li id="answerSheet401616957" data="401616957" class="active">58</li>
							                                <li id="answerSheet401616958" data="401616958" class="active">59</li>
							                                <li id="answerSheet401616959" data="401616959" class="active">60</li>
							                                <li id="answerSheet401616960" data="401616960" class="active">61</li>
							                                <li id="answerSheet401616961" data="401616961" class="active">62</li>
							                                <li id="answerSheet401616962" data="401616962" class="active">63</li>
							                                <li id="answerSheet401616963" data="401616963" class="active">64</li>
							                                <li id="answerSheet401616964" data="401616964" class="active">65</li>
							                                <li id="answerSheet401616965" data="401616965" class="active">66</li>
							                                <li id="answerSheet401616966" data="401616966" class="active">67</li>
							                                <li id="answerSheet401616967" data="401616967" class="active">68</li>
							                                <li id="answerSheet401616968" data="401616968" class="active">69</li>
							                                <li id="answerSheet401616969" data="401616969" class="active">70</li>
							                        </ul>
														</div>
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